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authorPaolo Bonzini <pbonzini@redhat.com>2014-08-20 14:29:21 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2014-09-03 10:03:35 +0200
commit00f034a12fdd81210d58116326d92780aac5c238 (patch)
tree6e1eb1f40e9914fa801bf128f1eed19543f665c2
parentfd2752352bbc98850d83b5448a288d8991590317 (diff)
downloadop-kernel-dev-00f034a12fdd81210d58116326d92780aac5c238.zip
op-kernel-dev-00f034a12fdd81210d58116326d92780aac5c238.tar.gz
KVM: do not bias the generation number in kvm_current_mmio_generation
The next patch will give a meaning (a la seqcount) to the low bit of the generation number. Ensure that it matches between kvm->memslots->generation and kvm_current_mmio_generation(). Cc: stable@vger.kernel.org Reviewed-by: David Matlack <dmatlack@google.com> Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/mmu.c7
-rw-r--r--virt/kvm/kvm_main.c7
2 files changed, 8 insertions, 6 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 9314678..323c3f5 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -236,12 +236,7 @@ static unsigned int get_mmio_spte_generation(u64 spte)
static unsigned int kvm_current_mmio_generation(struct kvm *kvm)
{
- /*
- * Init kvm generation close to MMIO_MAX_GEN to easily test the
- * code of handling generation number wrap-around.
- */
- return (kvm_memslots(kvm)->generation +
- MMIO_MAX_GEN - 150) & MMIO_GEN_MASK;
+ return kvm_memslots(kvm)->generation & MMIO_GEN_MASK;
}
static void mark_mmio_spte(struct kvm *kvm, u64 *sptep, u64 gfn,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7176929..0bfdb67 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -477,6 +477,13 @@ static struct kvm *kvm_create_vm(unsigned long type)
kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
if (!kvm->memslots)
goto out_err_no_srcu;
+
+ /*
+ * Init kvm generation close to the maximum to easily test the
+ * code of handling generation number wrap-around.
+ */
+ kvm->memslots->generation = -150;
+
kvm_init_memslots_id(kvm);
if (init_srcu_struct(&kvm->srcu))
goto out_err_no_srcu;
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